The present invention relates to a particle separator for the treatment of exhaust gases of an internal combustion engine. The invention can be used, in particular, for mobile internal combustion engines such as are provided, for example, in motor vehicles. The invention also relates to a motor vehicle having at least one particle separator.
The exhaust gas of an internal combustion engine generally contains pollutants and solids which, specifically taking into consideration the relevant regulations for the protection of health and the environment, must be removed. With regard to the solids, it has already been proposed to filter constituents of the fuel, such as for example soot or unburned hydrocarbons, sulfur compounds, etc., out of the exhaust gas and then (catalytically and/or thermally and/or chemically) eliminate or convert them. It is known for that purpose to use filters which have, for example, a porous wall, on or in which the solids are retained.
Aside from the solids generated from the burned fuel, the exhaust gas may have entrained in it additional particles which have a different origin and which are several times larger than the solids. Internal combustion engines and the associated exhaust systems are often subject to intense vibrations during operation. That can cause particles, in particular in the form of chips, pieces of coatings and deposits and parts of exhaust-gas treatment units, to become detached and, because they are entrained by the exhaust-gas flow, damage downstream components as a result of the momentum of the impact. Furthermore, the particles can lead to increased abrasion in moving components in the exhaust system, in particular a turbocharger or turbocompressor, as a result of an increased friction action in sealing gaps. Additionally, exhaust systems are known which recirculate a part of the generated exhaust gas to the internal combustion engine again (AGR/EGR: exhaust-gas recirculation), in such a way that in that case, there is likewise the risk of the internal combustion engine being exposed to such particles and thus being damaged.
It has now been found that, with progressive operating duration, the retained particles can cause problems. It must be taken into consideration in that case that the particles are, for example, ceramic and/or metallic and are not converted in the exhaust system. Consequently, the particles accumulate in the exhaust system, for example in the vicinity of a particle separator, and/or impact repeatedly against the latter. Such an accumulation of particles may lead to a local and/or fluctuating pressure loss in the exhaust-gas flow, which may result in undesired (power-reducing) effects in the internal combustion engine and/or the exhaust system. Furthermore, in that case, the strain on the particle separator also increases, in such a way that the stability of the particle separator takes on an increasing significance.
Furthermore, in the case of planar particle separators of that type, it was also found that the connection of a screen layer and the housing was in part technically very complex and thus also expensive to implement. Furthermore, it was also observed that, in continuous operation, the connection also became partially detached again, as a result of which, to some extent, new (metallic) particles were produced which then again posed a risk to the downstream components of the exhaust system.
A further problem with the particle separators is that the accumulated (ceramic) particles cannot be converted like the solids. It is therefore sought in this case, in particular, to find a way of cleaning the particle separators.